When diagnosing problems, technicians often use modem test equipment that provides the technician with graphical representations of data concerning the system being analyzed. For example, when analyzing the ignition system of a vehicle, an automotive technician is typically provided with data graphs representing the ignition signal (provided by the ignition system) to each of the vehicle's spark plugs. These data graphs may be displayed sequentially (i.e., one spark plug at a time) or simultaneously (i.e., all spark plugs at the same time). Further, in addition to ignition signals, other data signals may be monitored (e.g., coolant temperature signals, emission control signals, and fuel injector signals, for example), and it is often desirable to simultaneous display these signals so that the signals can be compared and their interaction researched.